Sound box for phonographs



Patented dan. 39, 1923.

,veyer arms between the stylus and dia whimbf,` S

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HENRY o. MARTIN, or nnxnanr, INDIANA.

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Application led January 23, 1922. Serial No. 531,232., l

To @ZZ whom t may `conce/rn.' 4 Be it known that l, HENRY C. Mnii'iiiy,a citizen of the United States of Anierica,,re

siding at Elkhart, in the countyof Elkhart? and State of indiana, haveinvented certain new and usefulV lmproveinents in Sound' Boxes forPhonographs, ot which the following is a specification.

The 4 present invention Vrelates particularly n to certain improvementsin instruments oi' the phonograph type involving the sound conve Tinwmembers which include the conphragm of the 'sound box, and the tone arm`or tubular sound conveyer between the sound box andthe amplifyingmember 'or amplifier, together with other correlated improvements aswill be hereinaiter niore'specifically pointed out and claimed. By theutilization of my invention sound conveying means are provided foraccurately recording `and reproducing sounds or tones with fullvymeasure and value that are clear and lifelike, and with the originalfull volume.

To this end the invention relates particularly to the construction ofthe sound conveying members, which are of increasing y conveyingcapacity, from the needle or stylus to the amplifier. `The thickness otthe inaterial of the walls of the conveyers also increases uniformly andgradually from the smaller end `of. the sound coiiveyer to the largerend, as will be `hereinafter specified and claimed.v i

,In the accompanying drawings l have illustrated one complete example ofthe physical yembodiment of my invention 'wherein the parts are combinedand arranged according to thel best mode l have thus `far devised forthe practical applica- ,tion of the principles of my invent-ion. n

Figure 1 is a top plan view, partly in section, of the adjustable,telescopic tone l the soundbox showing the diaphragm and,

the means of attaching, the conveyer arms thereto. i i

In the preferred form of the invention as y shown in the; drawings, thesound box des-- ignated as a' whole by the numerall is attached to the`tone armv and disposed at an angle to tlieplane ot the record diskcariiedcii the `turntable of the phonograph not shown, but which may beof suitable construction. V The angularly disposed sound'box thustravels' across the face ofthe disk in usual manner for recording andreproducing sounds. `ln yFigure l ity will be seen that the box includesar metallic circular base lplate 2 havingan open center yfor attachmentof the elbow or bend 3 of the tone arm el, andthe metallic elbow isfashioned with an exterior, annular vcollar ing head 6, there beinginterposed between the flange and head suitable non`-conduct `inggaskets or rings 7. The plate, head, and

elbow are secured firmly together by means or screws passing through theflanged iead and the base plate as shown.

.or flange 5 to be encased within theretain- The diaphragm 9 oit' thesound boxis pret- 'erably of mica, and is of peculiar and novelconstruction. lt is in the form of a circular disk, concavo convex inshape with its vconcavity toward the reproducing or recording stylus,and its maximum thickness vat its radial center, adjacent to the openingin the elbow of the tone arm. The edges of the diaphragm decrease in'thickness toward the periphery there-of, and this formation, togetherwith theconcavo-convex structure of the diaphragm, which is of `courseresilient insures a movement of ythe sound vibrations or waves in a moreconf centrated or central direction toward the outlet or opening of thesound box when recording,`and toward the inlet opening when reproducing,from whence thevibra tions or waves are distributed. The com parativelythin edges of the diaphragm are retainedpand secured to the base plateof the sound box, by a flanged retaining ring 10, and here alsonon-conducting gaskets,

ot rubber or other suitable material, are iny' terposed between thediaphragm and its re taining ring, vto prevent 'radiation of sound,V andthe retaining ring is secured'to the underside of the base plate byscrews 11.

Associated with the sound box are a multiplicity of sound conveyingarms,.here inl vdicated as five in number and designated respectively12, 13, le, 15, and 16, the arms increasing in capacity for conveyingsound waves or vibrations. rllliese arms are of resilient metal, andformed into helical coils iio similar to springs, and the succeedingarms from 12 through 16 are composed of wire of increasing gauge andconstitute successively heavier and less resilient conveyers, althoughall of the conveyer arms are resilientv tosome extent. The lower end ofeach of the arms, as indicated at 17 is brought to form an integral partof the stylus holder 18of usual form, and the needle19, which, becauseof the angular' position of the sound box,l is also disposed at an angleto the plane ofthe record, travels inthe groove usual, and is secured bythe set screw 2O in the holder.y n A l The upper end of each of theseconveyer arms, as 21, is secured in the diaphragm by means of upper andlower clamp nuts 22 and 23 as seen in Figure 4. The several conveyerarms are disposed about the center of the diaphragm, between the latterand the stylus holder, andare arranged symmetrically with ytheirrespective upper and lower ends brought into close formation. Theconveyer f arms differ, not only in the diameter of their 25 coils andgauge of thicknessv of the wire forming the coils, but they differ inlength of wire between the stylus and the diaphragm and the wire mayincrease in thickness toward the stylus.

The Vconveying or transmitting arms lead ing from the stylus or needleto the diaphragm, where they are centrally located at the maximumthickness of the diaphragm insure a maximum force of vibrations on thediaphragm, thereby influencing the vibrations to greater action in theircourse of development and amplification in the tapered tone arm 4forreproduction, and from the diaphragm to therecord in recordingsounds. n

The tone arm 4 is also designed with this purpose in view, and isadjustable as to its length for adapting it to different conditions,thereby bringing the voice or sound to be recorded closer to thediaphragm and record, thus enhancing or increasing the force of thevibrations at the recording point, resulting in a deeper and clearerrecord produced by the needle.

As best seen in Figs. 1 and 2 the tone arm is a telescopic structure,and includes an inner tubular section 24 having a split end sleeve 25with perforated ears 26, and a clamp screw 27 by means of which thesleeve, which embraces the upper end of the sound boxv elbow 3, issecured thereto in adjusted position for properly locating the sound boxand needle on the record. The exterior, telescopictube orfsection 28embraces the sec.-

tion 24 and isv movableuthereon, to extend or contract the length of thetone arm, there being sufficient frictional engagement betweenthe partsto hold thesections ofthe tube in adjusted location. The Vcross area, orinterior diameter of the tone arm increases with its distance from thevsound box, and the material in, or the thickness of the walls of thetone arm also increases with the distancel from the sound box. The outerend of the tone arm is embraced by a sleeve 29 of the horizontallydisposed elbow 30, the frictional contact between the sleeve and armbeing vsuch as to hold the parts in proper relation, and a verticallydisposed elbow 31 having an end sleeve 32 surrounds the reducedlextension 33 of the `horizontal elbow 30. The lower end 34 of thevertical elbow is encased within the larger sleeve 35 of the third elbow36, and these three elbows, which form the connection between the tonearm proper and the amplifier", also have the ratio of their interiordiameter, and the ratio of the thickness of their walls, increasedV withthe distance from the sound box.

lBetween the tone arm above the record and the amplifier beneath therecord, I employ a tone modifier, joining the ends ofthe dividedamplifier and adapted to be extended or contracted in linear direction,to provide deeper or lower tones,l and lighter or higher tonesrespectively. Usually thisV re-V sult is accomplished in phonographs byincreasing or diminishing the speed of the revolving Vor rotatingrecord, and is objectionable for the reason that the tempo or time isunduly altered. By the utilization of my modifier, the tempo or time4 isnot changed, although the tone is modified vas desired.

The structure employed inthe tone modiyfier involves the free end 37ofthe elbow 36, a horizontallydisposed Ushape tubular member having legs38 and 39, and the inf termediate bend 40, co-acting with 'sai'dend 37and a complementary end 4l of the am plier, a portion of whichisindicated as 42. In Figure 2 the modifier may be 'pulled outwardly orto the right to extend or elongate the amplifier at this point, or insimilar manner, the modifier may be moved t'o its contracted position,as in the drawing, the tubes 38 and 39 sliding on the tubular ends 37and 41. j

The gradual and uniform increase in the diameter of the conveyer or tonearm from the sound box through the tuning slide, and the correspondingthickness of the walls of the sound conveyer, assist in the developmentor amplication of the partials or fractions of sounds, before they reachthe amplifier, and stimulate the action of the sound waves, thusrendering theirE production more facile.

It will be understood thatthe length of the vtone arm may be Aextendedor 'contracted -through the relatively movable inner section 24 andouter section 28, and that the tone arm bodily. swings on the swiveljoint 311-35 beneath the elbow 31, as usual.

Having thus fully described my invention, what I claim as new and desireto seof a sound box and stylus holder, of a plu-` CII rality oftransmitting arms varying in length and composed of various but uniformthicknesses and eachhaving their respective ends connected withdiaphragm and stylus holder. r

2. The combination with the diaphragm of a sound box and a stylus, oftone transmitting arms of dissimilar'degrees of resiliency, varying inlength, and composed of various'but uniform thicknesses and each havingtheir respective ends attached to said diaphragm and stylus.

l 3. The combination in a recording and reproducing instrument includingthe diaphragm and stylus, of a plurality of tone transmitting armsVarying in length and formed in helicaly coils of different diameters,each having its respective ends ateters and composed of variousbutuniformy thicknesses, and each said arm havingl its respective endsattached to said diaphragm and stylus. t t

In testimony whereof I aiiX my signature.

HENRY f CQ MARTIN.

